Automaticity in the reading circuitry

Skilled reading requires years of practice to learn to associate visual symbols (graphemes) with speech sounds (phonemes). Over the course of the learning process, this association becomes almost effortless and automatic. Here we hypothesize that automatic activation of phonological processing circuits in response to a visually presented word is a hallmark of skilled reading. We used magnetoencephalography (MEG) to measure cortical evoked responses to printed words while children engaged in an attention-demanding fixation task in which their attention was directed away from the words. We found strong activation in brain regions involved in speech sound processing, namely the superior temporal gyrus (STG). This automatic response to visually presented words in a canonical language region was indicative of good reading skills: the visual stimulus-driven STG response was only present in skilled readers but not in children with dyslexia. Our results suggest that automatic recruitment of phonological processing circuits is a hallmark of skilled reading; with practice, reading becomes effortless as the brain learns to automatically translate letters into sounds and meaning.